<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  <script>
  var message="Hello World"
  function sayHello(){
    var message="HelloWorld"
    function hi() {
      var message="Hi kobe"
    }
    hi("hi中访问message",message)//作用域链
  }
  sayHello()
  </script>
</body>
</html>